Which planet in the Solar System was formed first?

According to scientists, the sequence of planet formation is not exactly the same as it is now. Earth was also not the first planet to form around the Sun.

Despite being the "youngest," Earth has the most ideal living conditions among the eight planets, partly thanks to the "support" from the giant planets that formed tens of millions of years before it - Photo: NASA

The sun was born first.

Approximately 4.5 billion years ago, a giant cloud of gas in space was pulled down by gravity, giving birth to the Sun, the central star of the planetary system in which we live.

The remaining gas and dust don't disappear but spread out into a disk of matter rotating around the Sun. Within that disk, tiny dust particles begin to collide, stick together, grow into rocks, and then into objects large enough to become planets. This process is called accretion .

When the Sun was in its early stages, there was a temperature boundary in the disk where gases and water could freeze, called the snowline . This boundary lies roughly halfway between present-day Mars and Jupiter .

Beyond the icy crust , matter with more ice is more likely to coalesce into giant planets like Jupiter, Saturn, Uranus, and Neptune .

Inside the snow-covered ice sheets , there is less gas and dust, so planets like Mercury, Venus, Earth, and Mars form more slowly and are smaller.

The sequence of planet formation

Based on computational models and observations from telescopes, astronomers believe that Jupiter and Saturn were the two earliest planets to form, just a few million years after the Sun appeared.

Next come Uranus and Neptune , within approximately 10 million years.

Inner planets, including Earth, take at least 100 million years to fully develop.

In other words, the distant giant planets are the "big brother," while Earth is the "youngest sibling" of this planetary system.

Although they are separated by nearly 90 million years , on a cosmic scale, that's just "a blink of an eye," less than 1% of the universe's age.

Planets also "migrate".

Interestingly, planets don't stay "still" from birth. After formation, they move , some moving closer to the Sun, others drifting further away, before settling in their current positions.

Jupiter once moved closer to the Sun, drawing in some small planets and pushing many asteroids away or into the asteroid belt. Neptune also pushed millions of small objects to the edge of the Solar System, creating the Kuiper Belt, home to dwarf planets like Pluto.

Importantly, thanks to Jupiter's gravitational pull and orbit, Earth was "pushed" into the habitable zone (Goldilocks Zone), which is neither too hot nor too cold, providing ideal conditions for liquid water to exist and for life to emerge.

Without Jupiter, it's highly likely that Earth would be somewhere else, and life as we know it today… might not exist.

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MINH HAI

Source: https://tuoitre.vn/hanh-tinh-nao-trong-he-mat-troi-duoc-sinh-ra-truoc-20250521203901639.htm